1. Field of the Invention
The present invention relates to a process cartridge and an electrophotographic image forming apparatus to which a process cartridge is to be mounted, for forming an image.
In this case, the electrophotographic image forming apparatus is an apparatus for forming an image on a recording medium by using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer and an LED printer), a facsimile apparatus, and a word processor.
Further, the process cartridge has a construction in which a charging device, a developing device, or a cleaning device, which serves as a process unit, and a photosensitive drum, are integrally formed into a cartridge, and the cartridge is structured to be detachably mountable to an electrophotographic image forming apparatus main body. In addition, the process cartridge has a structure in which at least one of the charging device, the developing device, and the cleaning device, and the photosensitive drum are integrally formed into a cartridge so as to be detachably mountable to the electrophotographic image forming apparatus main body. Further, the process cartridge has a structure in which at least the developing device and the photosensitive drum are integrally formed into a cartridge so as to be detachably mountable to the electrophotographic image forming apparatus main body.
2. Description of the Related Art
Conventionally, in an electrophotographic image forming apparatus, there has been employed a process cartridge system in which a photosensitive drum and a process unit acting on the photosensitive drum are integrally formed into a cartridge, and the cartridge is structured to be detachably mountable to an electrophotographic image forming apparatus main body. According to the process cartridge system, maintenance of the apparatus can be performed by a user himself/herself without depending on a service person, thereby drastically improving operability of the apparatus. Accordingly, the process cartridge system is widely used in a field of the electrophotographic image forming apparatus.
In the electrophotographic image forming apparatus, light such as a laser beam, light from an LED, or light from a lamp corresponding to image information is applied onto the photosensitive drum. As a result, an electrostatic latent image is formed on the photosensitive drum. Then, the electrostatic latent image is developed by a developing apparatus. Further, a developer image formed on the photosensitive drum is transferred onto a recording medium. Thus, an image is formed on the recording medium.
In the above-mentioned process, it is necessary for the process cartridge to be exposed to the outside at a position thereof where the photosensitive drum is opposed to the recording medium when the process cartridge is mounted to the electrophotographic image forming apparatus main body, and at a portion thereof opposing the process unit provided on a side of the apparatus main body, which acts on the photosensitive drum.
In view of the above, the process cartridge is provided with a protecting cover detachably attachable to the process cartridge so as not to damage a surface of the photosensitive drum at the time of insertion or distribution of the process cartridge. At the time of using the process cartridge, the process cartridge is mounted to the electrophotographic image forming apparatus main body in a state where the protecting cover is detached.
For example, Japanese Patent No. 3,535,604 (which was granted to Japanese Patent Application Laid-open No. H08-292706) discloses a method of inserting the process cartridge by using the protecting cover. In the method, the protecting cover detachable in a longitudinal direction is provided, and a convex portion formed on a lower portion of a leading end of the protecting cover in an insertion direction is fitted into a concave portion of the electrophotographic image forming apparatus main body, to position the protecting cover, thereby guiding the process cartridge to be mounted to the apparatus main body.
In the present invention, the above-mentioned structure is further developed.
In the construction of the related art, the positioning of the process cartridge is performed merely by fitting the convex portion of the protecting cover into the concave portion of the electrophotographic image forming apparatus main body. Accordingly, when the process cartridge is mounted to the apparatus main body, it is necessary to grip the protecting cover with one hand such that the protecting cover does not move, and to press the process cartridge to be inserted into the apparatus main body with the other hand.